I've been working on a variant of the latter idea on and off for about 4 years now. We got some funding (through an NSF grant) but I couldn't maintain full-time development on it. I'm presently working on a project that sprang up after I identified problems in the original design.
I'd love to hear more about your ideas; ping me @gmail if you want to chat.
Ah, but this is if money doesn't matter :-) My job is very challenging, and after eight hours at work, I can't sling code anymore, much less tackle an entirely different set of technologies than I use at work. Also, I don't think I could do justice to the idea without being face-to-face with teachers and students, which would be a full time commitment. I can't put myself in a position where I'll end up disappointing either my employer or a classroom full of kids.
My current job pays well, though, and I plan on retiring at least fifteen years before I'm too old to program, so the "money doesn't matter anymore" scenario is a realistic one. I have a feeling that whenever I retire, educational software will still feel like the right thing to work on.
I'd love to hear more about your ideas; ping me @gmail if you want to chat.